The Eiffel Tower was never built to last, but 128 years after the “temporary” iron structure was opened it is not just still standing, but has become an instantly recognised symbol of Paris and a magnet for as many as 7 million visitors a year.

Now, the city authorities have announced plans for a much-needed €300m (£262m) renovation, which will take place over the next 15 years and will include modernisations to improve security, reduce the long queues to get in and protect visitors waiting in the rain and snow.

The announcement comes as Paris bids to hold the 2024 Olympic Games and the Universal Exhibition the following year.

The city’s mayor, Anne Hidalgo, said it was important to “enhance this symbolic monument that has such a central role in the appeal of Paris to tourists”.

The new investment represents a 45% increase on the €13.7m the city currently spends each year to maintain the tower.

The deputy mayor of Paris, Jean-François Martins, who is responsible for tourism, said half of the money would be spent on overhauling the tower, including its lifts, which still use some of the original workings Gustave Eiffel installed. The thousands of lights that illuminate on the hour every evening will also be modernised.

The Eiffel Tower is lit in the colours of the French flag following the November 2015 terrorist attacks in Paris. Photograph: Joel Saget/AFP/Getty Images

The rest will be used to improve visitor facilities.

“There could be one or more places for the public to wait that are sheltered. Today, they are queueing in the rain and snow, and that’s not the best welcome for our foreign tourists,” Martins said.

Increased security demands following the terrorist attacks in Paris and across France in the last two years also require measures to reinforce and protect the tower, Martins added.

City officials said the most important work would be completed before 2024.

La Tour Eiffel was built to mark the 1889 Universal Exhibition in Paris, and was intended to be pulled down and scrapped in 1909. Paris officials decided to save it, however, after realising that the tower, at the time tallest building in the world, could be used as a radiotelegraph station.

It underwent a major facelift in 1986, and in 2014 the first floor reopened after two years of renovations, including the installation of glass panels in the floor. The work, which cost €30m, was paid for by SETE, a private company that runs the tower, in which the city authorities hold a 60% stake.

The tower is entirely repainted in its original grey every seven years, a task that takes 20 months and requires 60 tonnes of paint.

In recent years, the Eiffel Tower has been used to express solidarity and send messages at times of mourning and celebration, and to mark international events in the French capital.

Last November, part of its original cast-iron spiral staircase measuring 2.6m and made up of 14 steps that originally linked the second and third floors, was sold at auction for more than €500,000.

The renovation proposals will be presented for approval to the Paris council at the end of this month.