Jess Fox has set up another assault on double gold at the canoe slalom world championships after easing into the kayak semi-finals in London.

The Australian Olympic champ, who's the most decorated paddler in the sport's history, now has a chance of adding to her 13 world golds as she's safely negotiated her way towards the medal stages of both Friday's canoe (C1) event and Saturday's kayak (K1) competition.

Fox, who'd suffered a scare on a wild and wet Wednesday while battling to book her spot in the canoe semis at the Lee Valley Whitewater Centre, had no such problems 24 hours later once the sun came out as she proved the second-best qualifier for the K1 semis.

Fox, whose twice achieved the C1/K1 golden double at the same championships, reckoned she felt some relief after her difficulties the previous day.

"The conditions were amazing this morning, the sun's out there, no wind, I'm in a short sleeve shirt, so really happy to be racing and happy to put a good run down," Fox told the Paddle Australia website.

She was bettered only by her old German rival, event favourite Ricarda Funk, the reigning world and Olympic champ.

"To be racing today with pretty good conditions makes a huge difference. You can focus on your lines, and attack it a bit more," added Penrith's 29-year-old Fox.

"This course is not the hardest course we've seen, so that means the margin for error is absolutely tiny. I was really keen to put down a good run with no mistakes to go through on the first run."

Kate Eckhardt needed a second run before joining her illustrious compatriot and booking her place in the 30-paddler K1 semi-finals.

Tim Anderson was fifth fastest in the men's K1 qualifiers, automatically booking his place in Saturday's semis, where he'll be joined by teammates Lucien Delfour and Ben Pope, completing a successful day for the Australian challenge.