Labor challenger Kylie Gaston said she had knocked on more than 1000 doors, and she had fought for some strong government election promises, but it hadn't been enough.

"It was really great campaigning with good policies, but it was always going to be a mountain to climb," she said. "In the end, people wanted to stay Liberal, that's what the voters decided."

Ms Gaston congratulated Ms Britnell on her "impressive" victory, saying Labor's statewide win eased the pain of the local loss. "It's pleasing Labor has prevailed and we're going to have all those great policies implemented," she said.

Independent candidate Carol Altmann said she knew turning the seat out of Liberal hands for the first time would be "an uphill battle" but she'd "given it everything, boots and all".

"I'm extremely happy with getting 15 per cent of first preferences. Given it's my first go, I think that's extraordinary," she said. "In a couple of booths we actually beat Labor too, which is great."

Ms Altmann said a couple of factors hurt her cause, one of which was the "anti-Dan sentiment, which I think pushed the Liberal vote higher".

"The other thing of course was the two late independents (James Purcell and Jim Doukas) coming in, which really threw the rock under the wheels and destroyed the pathway we might've had," Ms Altmann said. "Overall, given what happened with the late entrants I think we hung on really well."

Ms Altmann said she worried for South West Coast facing four more years with an opposition MP. "It's just four more years of being overlooked."

Mr Purcell, who entered the race with only two weeks to go, said he wasn't surprised to see his vote drop to six per cent, down from 16.5 per cent in 2018. "It was a very short campaign, so I kind of tipped my vote would drop," he said. "But I was surprised by how much Roma won by. It didn't feel like that during the two weeks of pre-poll," he said.

Greens candidate Thomas Campbell, whose primary vote also dropped a percentage point from 2018, down from 6 to 5 per cent, said Ms Altmann may have eaten into his supporter base. He said people may have voted strategically with a left-leaning independent on offer.

He said Ms Britnell's tally showed she had built a profile in the electorate after seven years as MP. "Roma's very well known across the electorate. It seems like she has established herself now, and she'll obviously be there for the next four years at least," he said.

He said the result showed the seat wasn't yet ready to flip.

"If you look at the independent result in South West Coast, it's about 25 per cent, but it still comes down to how people list their preferences, and people seem to still lean conservative."

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