MEXICO CITY, Oct 3 - Mexico's inflation likely sped up again in September, a Reuters poll showed Monday, to an almost 22-year high, reinforcing expectations monetary policymakers will continue to hike the country's benchmark interest rate.

The median forecast of 15 analysts sees annual inflation accelerating to 8.74% in September, up from 8.70% in August when it reached its highest level since December 2000.

Last week, Mexico's central bank raised its key interest rate by 75 basis points to a record 9.25%, citing the "ongoing tightening of global financial conditions" and an environment of uncertainty as challenges.

Banxico, as the central bank is known, has raised rates by 525 basis points since the current hiking cycle began in June 2021 in a bid to tamp down inflation, which has blown past the bank's target of 3% plus or minus 1 percentage point.

"In our assessment, the case for a follow-up 75 basis points rate hike in November remains compelling given intense and highly disseminated inflation pressures, further deterioration of inflation expectations, and hawkish actions and guidance (from) the FOMC and other core central banks," Goldman Sachs economist Alberto Ramos said.

The Mexican central bank's next meeting, the second-to-last of the year, is scheduled for Nov. 10.

On Monday, Mexico's government announced an anti-inflationary plan made in agreement with food producers and retailers to keep food prices affordable.

Annual core inflation, which strips out some volatile food and energy prices, was forecast to reach 8.34%, the highest rate since August 2000, according to the poll.

In September alone, Mexican consumer prices are estimated to have increased by 0.67%, while the median projection for monthly core inflation was seen at 0.74%.

Mexico's statistics institute will release inflation data for September on Friday at 6 a.m. local time. (Reporting by Noe Torres; additional reporting by Gabriel Burin in Buenos Aires; Writing by Kylie Madry; editing by Jonathan Oatis)