A number of flights have been cancelled in Melbourne as thick smoke continues to cover the city and thunderstorms lash the state.

A Melbourne Tullamarine Airport spokesperson told 9News dozens of flights were suspended on Wednesday.

They airport is operating with a single runway and it will be “a number of days before flights resume at a normal rate.”

Most domestic flights on Thursday morning have been delayed.

You can check flight information for Melbourne Tullamarine here.

– With AAP