The 53-year-old, who created the show alongside James Corden, said Corden is “a really busy guy” juggling his movie career, his family and his chat show over in America.
While the 2019 Christmas special saw Jones’ character Nessa propose to Smithy, played by Corden, Jones said it would be better to have fans guessing what happened next.
Speaking to Jenni Falconer on Smooth Radio, Jones said: “We wouldn’t want to come up with something that was substandard.
“The last thing we want to do is disappoint.”
She added when she was working on the Christmas episode with Corden, they were trying to get Gavin and Stacey’s story right and they “hit a wall and we did think, ‘Oh let’s give up'”.
She said they then realised the story had to be about how the pair “keep that romance alive” from earlier in their lives.
“That scene when they go back to Barry Island and the re-enact when they declared their love for one another, and they went down memory lane, re-explored their relationship, it just gives me goosebumps even thinking about it now,” Jones said.
There is certainly an appetite for more Gavin and Stacey in the future. The Christmas special was watched by 11.6 million viewers, making it the biggest programme of the decade.
The BBC also decided to broadcast old episodes of the comedy again as a pick-me-up as the nation went into lockdown.
Jones has been coy about seeing the programme return in the future on previous occasions.
“At the moment there are no plans but then we didn’t have plans for years,” she told RadioTimes.com. “I wish I could say that we would do it but genuinely there are no plans at the moment.”
Additional reporting by PA.