BRASILIA, Nov 23 (Reuters) - Brazil's inflation outlook for next year rose for a fifth consecutive week, a central bank survey showed on Monday, prompting economists to raise their average year-end interest rate forecast to 3.00% from 2.75%.

Economists also raised their 2020 inflation outlook for a 15th straight week, according to the central bank's latest weekly "FOCUS" survey.

Inflation in Latin America's largest economy has spiked higher recently due to a surge in food and commodity prices fueled by a persistently weak exchange rate and supply shocks resulting from the COVID-19 pandemic.

Economy ministry and central bank officials insist the spike is "transitory" and has no bearing on longer-term inflation expectations, which remain well-anchored and significantly below the central bank's official targets.

But the continued creep higher is now filtering through to the interest rate outlook. Economists now expect the central bank's Selic rate to end next year at 3.00%, compared with 2.75% last week.

That would imply 100 basis points of tightening from the current record low 2.00%.

The FOCUS survey of around 100 economists on Monday showed the average end-2021 inflation forecast rose to 3.4% from 3.2% the week before.

That would still be below, but getting much closer to, the central bank's official 2021 goal of 3.75%.

The average end-2020 inflation forecast rose for a 15th week to 3.5% from 3.3%, still well below the central bank's 4.00% target. A month ago, however, the forecast was 3.0%.

Central bank President Roberto Campos Neto said recently that the spike is "temporary, but we are obviously monitoring it." (Reporting by Jamie McGeever; Editing by Alex Richardson)