* Regulator blocked Asda merger with Sainsbury's in April
* Asda CEO thinks Walmart would keep majority stake in any IPO
* Says Walmart "very supportive" of Asda since deal failure (Adds detail)
By James Davey
LONDON, July 3 (Reuters) - The timescale for a possible stock market listing of British supermarket group Asda, by its U.S. parent Walmart, is two to three years, Asda's boss said on Wednesday.
Walmart said in May it would look at an initial public offering (IPO) for Asda after Britain's competition regulator blocked a 7.3 billion pound ($9.2 billion) takeover by rival Sainsbury's.
"If I was a betting man, I just think that is the sort of time the process will probably take," Asda Chief Executive Roger Burnley told Reuters.
"I use the phrase specifically that we're 'minded' to an IPO," he said, explaining that both Walmart and Asda had not reached a firm decision or were at a point of discussing a specific date.
Walmart, which purchased Asda for 6.7 billion pounds in 1999, was not in any rush.
"There's no burning platform, it's whatever Walmart feel would be the best to make Asda successful and sustainable long term," said Burnley.
Asked if Walmart was likely to retain a majority stake in Asda if it did decide on an IPO, he said: "I very much think so."
Burnley, CEO since January 2018, said Asda would work to convince investors in the meantime that the company has a bright future.
"We need to be performing in the short term, create growth in the medium term and create a sustainable story in the long term."
Speaking on the sidelines of Asda's "Christmas in July" event where it showcases its festive product line-up, Burnley said Walmart's support has been "very strong" since the failure of the Sainsbury's deal.
"Walmart will listen to any investments I want to make for sure, to make us sustainable into the future," he said.
Burnley's strategy is focused on lower prices to narrow the gap with German-owned discounters Aldi and Lidl, more innovation in own-brand products, better store standards and improvements in e-commerce operations.
Though Asda has reported eight straight quarters of underlying sales growth, in May it warned of an "increasingly challenging backdrop".
"We're definitely in tough times, we're in a little bit of a perfect storm," Burnley said of the UK macro economic backdrop.
Echoing comments earlier on Wednesday from Sainsbury's, he pointed to ongoing uncertainty around Brexit and a tough comparison with the same period last year when Britain enjoyed record hot weather and major events including a royal wedding and the men's soccer World Cup.
In common with market leader Tesco and Sainsbury's, he also said planning for a disorderly no-deal Brexit on Oct. 31 would be more difficult than the original March departure date because logistics networks will be full of Christmas stock. (Reporting by James Davey, Editing by Paul Sandle and Elaine Hardcastle)