British finance minister Rachel Reeves should ensure public debt remains on a downward path if she makes changes to fiscal rules in her first budget next week, International Monetary Fund chief economist Pierre-Olivier Gourinchas said on Tuesday.

Gourinchas said the IMF would assess changes when they were announced, but that Reeves should bear in mind the IMF's general advice for advanced economies with high levels of debt.

"There is a need to bring debt levels down, stabilise them when they are not stabilised and rebuild fiscal buffers," he told reporters at an IMF press conference to present its annual economic forecasts.

"If you're not doing that, that's when you potentially find yourself later on at the mercy of market pressures that will force an adjustment that is uncontrolled to a large extent," he added.

(Reporting by David Lawder and David Milliken; Editing by Kevin Liffey)