Incoming independent MP Nicolette Boele says Labor should send clearer signals to investors about climate change and energy supply, warning business confidence on the transition to renewables is being held back.

Boele was declared the winner in the Sydney seat of Bradfield this week, after a month of counting and recounting in her race against Liberal Gisele Kapterian.

She is preparing to take her seat in parliament after securing a wafer-thin victory of 26 votes. The blue-ribbon Liberal seat was previously held by Paul Fletcher.

A former management consultant and climate expert, Boele said Labor should consider implementing a price on carbon or other decisive policy settings to supercharge renewables investment.

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She made the comments in an interview for Guardian Australia’s Australian Politics podcast, released on Friday.

“This Labor government, so far, is still walking both sides of the fence and it’s confusing as hell for the private sector in terms of investing their money. Do we continue to invest in coal and gas, and for how long, or do we double down on the renewables?

“If we just had some certainty – some long, loud and legal signs from the government about a direction and pace of travel on climate – we could have literally tens, if not hundreds of billions of [dollars of] investment from superannuation, private wealth, flowing into those solutions in large scale wind, and solar, and storage and batteries, and energy efficiency, and all of those things,” she said.

“But we haven’t had it, and that is where it’s not so much big or small government – it’s about just smart government.

“Government has a role to be clearer with what its policy directions and settings are, and you’ll see just how amazing the business community can be … because as soon as they smell an opportunity to make some money, and do good and have fun, people want to go on board that bandwagon for sure.”

Boele said the environment minister, Murray Watt, should face tougher scrutiny over his decision to approve Woodside’s expansion of the North West Shelf gas project to 2070, a development she called “a climate bomb”.

“This is a party that I thought did understand the climate science. I’ve been watching the treasurer managing the economy in the last term, and [he’s] done, frankly, quite a formidable job in that,” she said.

“This decision, for example, just makes no sense to me economically, scientifically. There’s got to be a political reason why it’s happened.”

Anthony Albanese defended the North West Shelf decision on Friday, telling ABC radio in Melbourne that Watt had to assess the application based on strict interpretation of the Environment Protection and Biodiversity Conservation Act.

Bradfield was the last outstanding seat from the 3 May election, but the result could still be challenged by the Liberals in the court of disputed returns.

Kapterian said in a statement she would carefully review the count, stopping short of congratulating Boele. Any candidate or elector from the seat can challenge the result within 40 days of the return of the election writ.

But Boele said she was confident the result would withstand by possible legal challenge.

“I had intrinsically felt that our democracy is one of the best in the world, that the electoral commission is not only independent, but very well run, and very thorough. And watching this process has given me that confidence.

“Built into the system is the court of disputed returns and that is an important check and balance as well. So if the other side wants to challenge, that’s completely their prerogative.

“It’s a tiny, tiny margin, but it’s a definitive one,” she said.